"Every rocket fired by Hamas is meant to kill Israeli civilians. Every rocket is a war crime," it added.

Any deaths from the misfire are likely to be cast as "civilian casualties" from IAF retaliation in the international media.

The Islamic Jihad's "armed wing," the Al-Quds Brigade, took responsibility for firing "three Grad rockets at Ashkelon" in a statement. All three reportedly fell in open areas.

Israel has yet to confirm an official response to the rocket fire, but Palestinian media sources reported close to 10:00 am a possible airstrike in northern Gaza.

Shortly after the first rocket salvo was fired, Hof Ashkelon Regional Council head Yair Farjun told Channel 2 that the time has come for Israel to respond decisively to the break.

"Israel needs to give a hard smack to the head of Hamas," Farjun said. "There will be no refuge."

Truce or fire?

Meanwhile, Hamas has insisted that talks in Cairo to pressure Israel into a permanent agreement will continue - even though the terrorist group rejected the notion of extending the "humanitarian ceasefire."

"All the Palestinian factions, including Hamas, have agreed not to renew the ceasefire because (Israel) is refusing to accommodate our demands, but negotiations continue in Cairo," Hamas spokesman Fawzi Barhum told AFP.

Earlier Friday, both Hamas and Islamic Jihad leaders announced that they rejected the possibility of extending the 72-hour ceasefire brokered in Cairo, citing Israel's failure to accept their laundry list of unprecedented demands.

"We have one position, we refuse to extend the ceasefire, it is a final decision. Israel did not propose anything," said one senior Hamas official after a long meeting with Egyptian mediators.

The demands included removing all transportation and import restrictions on Gaza; building a seaport and an airport accessible to Palestinian terrorist groups; and releasing terrorists re-arrested in Israel since the 2011 Gilad Shalit deal - all measures designed to prevent Hamas and others from rearming and threatening more Israeli lives.